Showing papers on "Biogas published in 1980"

Methane Production From Waste Organic Matter

Abstract: The primary emphasis of this reference book is the application of anaerobic digestion to produce methane gas from several types of waste organic matter. The text begins with an introduction of different types of digesters and a brief description of the various modes of operation in practice. The second chapter presents a world survey on anaerobic digestion emphasizing some interesting applications especially in isolated areas where a digester not only is used to extract energy from animal wastes but it also stabilizes the waste for land application. The next four chapters describe the anaerobic digestion process. Though the information is not new, it introduces the reader to the nature of the microorganisms active in a digester, the biochemical transformation taking place that ultimately produce methane gas and a stable sludge for land application or disposal, and generally accepted design criteria. A chapter on digester gas presents the characteristics of the component gases such as carbon monoxide, hydrogen, and hydrogen sulfide. Several tables show both the physical characteristics and the physiological effects of the important component gases. Of particular interest are the examples given for both on site and off site usage of the digester gas. The next two chapters focusmore » on operation problems and methods of controlling digester performance. In Chapters 9 and 10, Digester Potential with Specific Waste Materials and Benefits of Anaerobic Digestion, respectively, the authors emphasize that anaerobic digestion seems to be the most promising method for utilizing biomass of a high-moisture content. The book concludes with the potential commercial aspects of digestion that have already begun to be recognized throughout the world.« less

Methane production by anaerobic digestion of plant material and organic waste

Abstract: A process for production of methane gas in higher yields and higher rates by thermophilic or mesophilic anaerobic digestion of plant material and/or organic waste in admixture with an extract of different plant material. Increases of methane yield of greater than about 25% and up to about 500% are obtained by addition of the extract of different plant material to a normally low biodegradable plant and/or organic waste material before anaerobic digestion thereof. The resulting methane yields and production rates are higher than those obtained by the sum from anaerobic digestion of the individual components when using the extract as taught by this invention.

Methane production from and beneficiation of anaerobic digestion of plant material and organic waste

Abstract: A process for improved methane production resulting in higher yield and higher production rates by anaerobic digestion of a mixture of plant material and organic waste. The process is suitable for production of synthetic natural gas and through anaerobic digestion of a mixture of plant material and organic waste allows better matching of organic waste and plant material feed supplies for year round operation. The process of this invention results in digester effluent which is easily dewatered and has a low concentration of soluble organics, providing easy disposal and recycling to the digester. The process of this invention may be used for methane production from plant material which is, by itself, recalcitrant to anaerobic digestion.

Fuel Gas Purification with Permselective Membranes

Abstract: Production of fuel gas from biomass and recovery of flared gas from landfills, oil fields, coal mines, is hampered by the high cost of gas purification for the removal of C02 and H2S. Membranes offer a potentially simple and attractive technique for on-site gas purification. Two membrane approaches have been considered for fuel gas purification-polymer films and facilitated transport-each with its own unique advantages. Polymer films can be made extremely thin (<500A), and thus have high gas throughput and a very low membrane area requirement. Ultrathin polymer membranes have been found to be extremely attractive for purification of gas produced from waste or in remote site applications. Of particular interest is biogas produced from anaerobic digestion of sewage, municipal waste, agricultural waste, and landfills. Membrane purification is expected to cost less than half of that for conventional scrubbing processes. Additionally, the gas is purified and dried at the same time. Laboratory tests co...

Methane gas production for dairy manure at high solids concentration

Abstract: A70 L anaerobic digester was operated with undiluted dairy manure (average total solids—20 percent for a 41-wk period. The loading rate was gradually increased for the first 28 wk to 11.6 g VS/L-d and was maintained at this level for the remaining 13 wk. Feeding the digester at this loading rate every other day established a deten-tion time of 15.1 d. During the last 13 wk the average total gas production, corrected to 20 °C and 1 at-mosphere pressure, was 2.1 L/L digester-d. The methane content of this gas averaged 51.3 percent. Ap-proximately 25 percent of the volatile solids were destroyed under these operating conditions. Use of un-diluted manure and auger mixing for 10 min every half hour prevented scum formation.

Biogas from a High Solids Combination of Dairy Manure and Barley Straw

Abstract: AO. 10 m3 anaerobic digester was operated at 35 °C for 54 weeks using a high solids content feed of dairy manure and chopped barley straw (approximately 17 percent TS). The straw was combined with the manure at a ratio which increased the non-lignin carbon to nitrogen ratio of the feed to 30. Four successive phases of opera-tion during this time were carried out at successively shorter retention times of 25, 20, 15 and 10 d and cor-responding higher loading rates of 5.2, 6.5, 8.7 and 12.5 kg VS/m3,d. At the highest loading rate the total gas production, corrected to STP, was 2.46 Vol/Vol * d. No scum layer was observed under these operating condi-tions despite the use of potentially floatable barley straw.

Anaerobic fermentation of agricultural residue: potential for improvement and implementation. Final report, Volume II

Abstract: Earlier studies have shown that although large quantities of agricultural residues are generated on small farms, it was difficult to economically justify use of conventional anaerobic digestion technology, such as used for sewage sludge digestion. A simple, unmixed, earthen-supported structure appeared to be capable of producing significant quantities of biogas at a cost that would make it competitive with many existing fuels. The goal of this study was to define and demonstrate a methane fermentation technology that could be practical and economically feasible on small farms. This study provides the first long term, large scale (reactor volumes of 34 m/sup 3/) parallel testing of the major theory, design, construction, and operation of a low cost approach to animal manure fermentation as compared to the more costly and complex designs. The main objectives were to define the lower limits for successful fermentor operation in terms of mixing, insulation, temperature, feed rate, and management requirements in a cold climate with both pilot scale and full scale fermentors. Over a period of four years, innovative fermentation processes for animal manures were developed from theoretical concept to successful full scale demonstration. Reactors were sized for 50 to 65 dairy animals, or for the one-familymore » dairy size. The results show that a small farm biogas generation system that should be widely applicable and economically feasible was operated successfully for nearly two years. Although this low cost system out-performed the completely mixed unit throughout the study, perhaps the greatest advantage of this approach is its ease of modification, operation, and maintenance.« less

The production of biogas from cattle slurry: the effects of concentration of total solids and animal diet.

Abstract: 3available for degradation to methane and carbon dioxide. The efficiency of gas production however, decreased with increasing TS concentration yielding up to 60% more gas/kg TS at 1% TS than at 8%. There was a significant difference in the gas production fro. the slurries derived from animals fed the two contrasting diets, with the sugar cane based diet giving consistently higher yields. Physical conditions of pH and organic solids concentration would appear to favour the molasses/grass diet. It is suggested that the higher C:N ratio is the reason for the superiority of the sugar cane diet

Process and apparatus for the production of biomethane by anaerobic fermentation of straw, manure and similar materials

Abstract: 1. Device for the anaerobic fermentation of manure with a view to the production of bio-methane, this device being characterized in that it comprises a reactor, into the bottom part of which is introduced the manure in a reactional aqueous medium, this manure progressing during fermentation towards the top part of the reactor where the drawing off of the gas produced, separated from the solids is carried out, in that this reactor comprises a perforated vertical partition separating it internally into two compartments, the first receiving the manure and the second, at least in part, occupied by a porous packing of fixation of the microorganisms, ensuring the fermentation, and in that a recycling decanter is associated to the reactor, this decanter being fed from the second compartment of the reactor by the liquid fraction evacuated from the reactor that it separates into one part enriched in recycled microorganisms towards the second compartment, and a second impoverished part that is rejected.

Sewage: Waste or Resource?

Abstract: This article contains a historical review of sewage, its collection and disposal, its treatment and its application. It was not until the second half of the 19th Century that it was realized, that sewage should be returned to the soil where its immense fertilizer value would prove a source of prosperity. The production of biogas and/or alcohol has been largely overlooked and the utilization of sewage as a renewable resource is urged.

Methane production rate studies and gas flow modeling for the fresh kills landfill. Interim report

Abstract: Methane is produced in landfills by anaerobic bacteria in the digestion of various organic materials found in the wastes. With the increasing cost of fuels the recovery of methane can be economic from some landfills. The rate of methane production can vary widely depending on factors such as the moisture content of the wastes, the pH, toxicity, temperature and amount of organic material available. Information regarding the rate of gas production and gas flow during pumping is needed to determine the potential of a site for methane recovery and in the design of a recovery system. The primary objective of this study was to develop gas flow models based on measurements of the pressure differential between landfill gas and atmospheric pressure that would enable the rate of gas production to be estimated. In the course of this investigation two landfill gas flow models were developed; a static model and a dynamic model.

Design and operation of small biogas plants

Abstract: This paper concentrates on the experience gained from the adaptation of the Chinese biogas technology to rural areas of Egypt. Three different prototype digesters have been constructed. The first is a 10 M/sup 3/ rectangular digester of the water pressure type, the second is a 6 M/sup 3/ circular and shallow digester with domed roof and dished bottom. The third prototype unit with a capacity of 7 M/sup 3/ has been recently constructed. It combines the features of both plug flow and the Indian movable cap types. Provisions for solar heating of feed water, composting of effluent and attachments to both latrine and animal shed were incorporated in the unit. The structural theory, design criteria, construction technique and cost estimation of the circular digester are described. Some operation and performance data of the circular digester are presented. This covers the effects of variation of ambient temperature on internal temperature, effects of temperature and pressure on the gas production rate and composition.

Methane-production-rate studies and gas-flow modeling for the Fresh Kills landfill

Abstract: Methane is produced in landfills by anaerobic bacteria in the digestion of various organic materials found in the wastes. With the increasing cost of fuels the recovery of methane can be economic for some landfills. The rate of methane production can vary widely depending on factors such as the moisture content of the wastes, the pH, toxicity, temperature and the amount of organic material available. Information regarding the rate of gas production and gas flow during pumping is needed to determine the potential of a site for methane recovery and in the design of a recovery system. The primary objective of this study was to develop gas flow models based on measurements of the pressure differential between landfill gas and atmospheric pressure that would enable the rate of gas production to be estimated. In the course of this investigation two landfill gas flow models were developed; a static model and a dynamic model.

Production of Biogas from Wastewaters of Food Processing Industries

Abstract: An Upflow Anaerobic Sludge Blanket Process used in converting biodegradable, soluble, organic pollutants in industrial wastewaters to a directl~burnable biogas composed mainly of methane has been developed, tested, and commercially applied in Holland. Operations on wastewater from the processing of sugar beets have shown hydraulic retention times of less than 10 hours with reactor loadings of at least 10 Kg COD per m 3 digester volume per day and purification efficiencies exceeding 90%. Biogas production is at a rate of about 1 therm 3 (100000 BTU) per 10 Kg COD treated. A moderately sized (1000 m-) wastewater treatment plant processing the or~er of 10000 Kg COD per day will, therefore, produce the order of 1000 therms of energy per day while, at the same time, reducing the COD level in the effluent by an order of magnitude. The set of conditions required for efficient operation of this anaerobic process will be discussed. The process is unique in its mixed sludge bed approach allowing for tolerance of swings in Ph (6-8) at relati~ly low temperatures (32 0 C_38°C) which can be readily achieved from most wastewater streams with little expendi­ ture of additional energy. Sludge production is remarkably low, only about 5% of the COD loading, greatly alleviating disposal problems. These characteristics are conducive for the use of the anaerobic process to recover energy from a variety of wastewaters rich in carbohydrate-type substances as produced routinely as a by product of many types of food processing activities.

State-of-the-art report on methane fermentation of biomass

Abstract: Research and development on biogas have emphasized technologies for expediting natural methane generation from anaerobic digestion of biomass. This indepth study reviews the status of biogas technology in developing countries and assesses the feasibility and desirability of expanding biogas production. First, based on an extensive review of the literature, the principal technical, social, economic, and environmental issues associated with methane production from farm-and feedlot-scale biogas plants and from marine biomass, urban refuse, and landfill are delineated. The microbiological processes underlying anaerobic digestion and the influences of various environmental factors (e.g., mixing, heating, toxicity, pH, retention time, nutrients) on the digestion process are then described. Raw materials available for biogas, different biogas plant designs (e.g., Chinese, Indian, Philippine, and bag), and the maintenance, operation, and safety of biogas plants are discussed. Next, the composition, fuel value, and processing of biogas are examined; attention is also given to the uses of sludge by-products. The ecological, health, and sociocultural implications of constructing and operating biogas plants in developing countries are reviewed and the status of biogas technology is described. The authors conclude that in both developed and developing countries the energy value obtained through biogas generation is only slightly greater than the costsmore » involved. Thus, a major factor in implementing biogas projects is reclamation of by-products for animal feed and fertilizer. In rural areas where kerosene is expensive and labor inexpensive, a very simple biogas system prod« less